Wii U (especially WiiU) and 3DS have some serious attach rates

[Miyamotoo]

Mr.Playstation said:

Dreamcast:

Hardware: 8.20 Million
Software: 64.89 Million

Attach rate: 7.9  games/ console

Spaced out releases usually means that people are going to buy each new game and hence each games respective attach rate will be quite high.

GameCube:

Hardware: 21.7m

Software: 208.57m 

Attach rate: 9.6 games/ console